Data management is increasingly important as widespread access to public computer networks facilitates distribution of data. Distribution of data over public computer networks may be undesirable when the data in question comprises sensitive, confidential, copyright or other similar information.
A computer operating system can typically monitor input of data to a process or output of data by a process and apply appropriate management restrictions to these operations. Exemplary restrictions may prevent write operations to a public network, or to external memory devices for data having certain identifiable characteristics. However, manipulation of data within a process can not be monitored by the operating system. Such manipulation may modify the identifiable characteristics of data, and thus prevent the operating system from carrying out effective data management.
Particular problems arise when different types of data are assigned different levels of restriction, and processes involving data from different levels of restriction are run alongside one another. An operating system cannot guarantee that the different types of data have not been mixed. To maintain a desired level of restriction for the most restricted data in these circumstances, this level of restriction must be applied to all data involved in the processes. Consequently, data can only be upgraded to more restricted levels, leading to a system in which only highly trusted users/systems are allowed access to any data.
It is an aim of preferred embodiments of the present invention to overcome at least some of the problems associated with the prior art, whether identified herein, or otherwise.